At some point, everyone looks back on their achievements and says, “Why not do more?” Primary Weapons Systems is known for their piston driven wonderguns and TTAG has had the pleasure of testing their MK 114 rifle and MK 107 Pistol in the last few months. Short story, we’re impressed with what they’re putting out. But back in early May, PWS announced that they’d also be releasing a direct impingement (DI) upper for the masses. It still uses the same high quality parts and manufacturing processes Nick and I raved about in our reviews, but in a simple, more cost effective package. When you make one of the best piston guns out there, making a good DI gun shouldn’t be too hard, right? . . .
If you’ve seen one AR upper, you probably figure you’ve seen them all. Well, in a way, yes. To my amateur eye, the PWS DI upper doesn’t really deviate from the norm when it comes to structure, features, or appearance. The first and most important thing I checked was to see if it would fit on a variety of lowers. First test passed. It hooked up to ArmaLite, Palmetto, and New Frontier lowers with ease and exhibited no rattles or shimmies once in place.
As you can see, the upper features a Picatinny flat top along with forward assist and a dust cover. Again, features virtually all of Stoner’s descendants possess now.
Where the PWS starts to differ from the pack is in the barrel, bolt carrier group, and forend. You can easily find stripped uppers on the cheap, but they won’t have a free-floated forend, and they most likely won’t have a high quality barrel.
PWS uses a QPQ isonited barrel turned in house from a chrome moly blank. This means, a) that they have a high degree of control over the final product, and b) their barrels are corrosion resistant. As part of their turning process, they create a profile that sacrifices nothing in accuracy while being lightweight(ish).
PWS offers three configurations in their Modern Musket line, their nomenclature for DI guns. This test gun was of the 14.5″ barrel variety sporting a pinned and welded flash hider to meet NFA regulations. They offer two types in that class, one sporting the FSC556 muzzle device, and the other sporting the Triad. My test rifle used the Triad. There’s also a 16″ version that only comes with the FSC556 muzzle device.
All of the DI guns feature the PWS keymod rail, a free floated affair with a Picattiny upper portion and keymod everywhere else. One nice feature is the QD mounts at the front and back of the rail. The 14.5″ gun sports the 12.1″ handguard while the 16″ sports the 15″ length. Both the barrels and handguards are available as independent accessories from PWS in case you have a barrel/upper combo that’s working great for you, but you want a new or different handguard.
The PWS website indicates that their uppers are sold as stripped units, however PWS was nice enough to ship our test gun with a charging handle, and complete bolt carrier group. Truly a plug and play affair. If you’re interested in adding a BCG, PWS is happy to sell you one for $199.95. However, you’d still be responsible for finding a firing pin, bolt, and charging handle. If you’re one of those buyers who prefers a matched bolt and barrel, you should be able to call PWS and put together a solution. They’re great folks with an eye towards customer service.
I was pleased with the overall quality of the parts and assembly of the DI upper. As you can see, it checks all the boxes. Properly staked gas key? check. Full auto bolt carrier group? Check. M4 feedramps? Check. Free floated handguard? Check. 1:8 twist barrel? Check .223 Wylde chamber? Check. It all adds up to an incredibly reliable affair that eats .223 and 5.56 all day with boring repetition. It isn’t a featherweight upper, but the weight and balance is nice making it easy to handle, and the keymod system ensures you can stick whatever you want, anywhere you want. These are all things I’d expect for a product that will cost you nearly a grand when the dust settles.
But now lets discuss accuracy. I mounted an 8X scope, the Bushnell you see above, laid down at 50 yards, supported the front and rear, and put four different types of ammo downrange. The results are below.
Because that font is incredibly hard to see, I’ve presented the results below in handy bullet point fashion using both the Average to Center and Max spread measurements for group size.
- AE 223 (2915 fps)
- Max Spread: 2.649 MOA
- Average to Center: .842 MOA
- PMC Bronze (2867 fps)
- Max Spread: 1.688 MOA
- Average to Center: .562 MOA
- XM 193 (3251 fps)
- Max Spread: 2.572 MOA
- Average to Center: 1.123 MOA
- XM 855 (3172 fps)
- Max Spread: 5.058 MOA
- Average to Center: 1.908 MOA
As you can see, this gun HATES XM 855, a disappointing fact since I happen to have a pretty decent amount of it on hand. I was generally pissed about that flyer in the American Eagle group, and if I used a “best of” three-shot group, it would be a close to 1 MOA group. But five-shot groups keep us honest.
For repeatability sake, it eats PMC Bronze best, and that’s what I’ve had the most luck using. I’m sure that with the right ammo, this is a nearly sub MOA gun, but I wasn’t able to produce those kinds of results in my testing. Nick was able to get sub MOA results with their MK 114 so it might just be me, but I wasn’t overjoyed with the accuracy of this gun. Good for sure, and better than a lot of uppers out there, but not one of those guns that takes whatever you feed down the pipe, and drills ragged holes with it.
Specifications: PWS Modern Musket DI Upper
- Model: DI – 14LE
- Chamber: .223 Wylde
- Barrel Length: 14.5″
- Muzzle Device: Triad (pinned/welded)
- Barrel Twist: 1:8
- Gas System: Direct Impingement
- MSRP: $699.95 – stripped $674.95 online & $899.95 online for a complete upper
Ratings (out of five stars):
Build Quality * * * * *
This is a top notch upper in terms of construction. All the right pieces are there, and all the right actions have been taken including a properly staked gas key, M4 feed ramps, and full auto bolt carrier. Everything is assembled to perfection. I was unable to find any defects cosmetic or otherwise. Even the pin/weld job on the flash hider looked perfect.
Accessories/Modularity * * * * *
Since the PWS rail is a keymod system, your options are limitless. Feel free to stick a Picatinny section in every hole or be more judicious and add a light here or there, or a vertical foregrip. With the Keymod system, you can do anything you need to do.
Reliability * * * * *
I was unable to make it choke. I fed it four different types of ammo and some random grab bag stuff that could have been anything. I didn’t get so much as a hiccup during my testing. I was not at all a diligent owner either. I refused to lube it past what came from the factory, and subjected it to sand, dirt, and some rain. Nothing seemed to affect reliability
Accuracy * * * *
Update here
The PWS Modern Musket appears to eat cheap PMC for breakfast, lunch, and dinner and consistently turning in sub 2 MOA groups. This is perfectly adequate accuracy for the weekend warrior, and carbine match competitor. However, if you need to stretch the legs a bit, you can shell out a bit more for the heavier loads from Fiocchi, Federal, or Norma and see sub 1.5 MOA groups. This isn’t mind blowing accuracy by any means, but it is more than adequate to warrant a solid four star rating.
Overall Rating * * * *
This is a fine firearm. I would say that for most shooters, a gun that can go sub 1.5 MOA with premium ammo is enough of a shooter to not matter. It has all the right parts to put it in a class with other premium products, and the price to suit that placement. A similarly kitted out Noveske will run you north of $1300 so this represents a nice middle ground that will get you high quality features without absolutely destroying your bank account. If it’s any indication of my feelings on the gun, I’ll be using it for my upcoming run-and-gun race through the desert. I can only pick one gun and this one is it for me.